A citywide police search is under way for three burglars who broke into a Hong Kong jewellery shop and made off with an estimated HK$5 million (US$638,000) worth of valuables in the early hours of Thursday.

Officers were called to the ground-floor store on Castle Peak Road, Yuen Long, soon after 4am when the shop’s alarm went off. The three men had fled before police arrived.

It was the third burglary reported in Yuen Long district in 24 hours.

According to police, the store’s rolling shutter had been prised open. The three men had worn caps and masks, and had used hammers to break open display counters and grab gold ornaments.

“Jewellery and gold ornaments were stolen from the store,” one police source said.

Police said a gold necklace believed to be part of the haul was found on the pavement at nearby Yu King Square.